Saturday, May 30, 2009

Ida, the “missing” link

“Ida”, a 47-million-year-old primate skeleton has been unveiled amid much fanfare and a flurry of well-orchestrated media announcements. It coincided with the release of a book and a television documentary, both of which had been prepared under a cloak of secrecy.

For a fact, the fossil is a paleontologist’s dream come true. It belongs to a species named Darwinius Masillae (after Darwin and the place of its discovery Messel, Germany) and it has been exquisitely preserved. Parts of its last meal were found inside its stomach. We thus know that she (for the specimen is probably a female) was an herbivore who feasted on fruits, seeds and leaves. She was overcome by carbon dioxide gas whilst drinking from the Messel lake: the still waters of the lake were often covered by a low lying blanket of the gas as a result of the volcanic forces that formed the lake and which were still active. X-rays revealed a broken wrist which may have contributed her demise. Hampered by her broken wrist, Ida slipped into unconsciousness, was washed into the lake, and sunk to the bottom, where she was preserved for posterity. When she died she was approximately nine months old and she measured almost three feet high.

Ida lived at a critical period in Earth’s history called the Eocene. Earth was just beginning to take the form that we recognize today – the Himalayas were being formed and modern flora and fauna evolved. Following the extinction of dinosaurs, the ancestors of modern mammals, including primates, lived amid vast jungle. Till today, scientists’ most-valued fossils of primates from that era comprised mostly of teeth. It is therefore easy to imagine the scientific excitement about Ida. But is she the common ancestor of humans and apes? Is she really the “missing” link?

Behind the media hubbub lays a bitter scientific trench war with regards to human evolution. Follow the tree of human evolution backwards and when you reach around 6 million years into the past you are going to meet the common ancestor of humans and chimpanzees. Go further back several more million years and you arrive at a big enigma: when did the earliest “anthropoid” primates (who ended up as apes, monkeys and humans) split from their even earlier ancestors who were lemur-like? The question is paramount to scientists because lemurs and anthropoids differ in many significant ways. For example, lemurs have claws and anthropoids have fingernails.

There are three fractions battling it out with their respective theories. Firstly, the discoverers of Ida who think our ultimate ancestor is their finding, Ida the Darwinius, which belongs to a lemur-look-alike species called “adapids”. Then there are those who support that the ancestral split happened thanks to the “omomyids”, an extinct group that looked like tarsiers; and, lastly, there are those who contend that our great-great-great grandfathers were sweet-looking, wide-eyed primal tarsiers (whose descendants are still around today). The science team behind Ida has received considerable criticism for trying to “steal the show” by claiming that their specimen resolved the matter for ever.

The way scientists build a case for a species being the ancestor of another is by looking at certain anatomical characteristics that are common to the two species to the exclusion of others. Darwinius is linked to anthropoids on the basis of the absence of two common lemur characteristics: a tooth comb (a set of forward-facing incisors) and a grooming claw (a special claw on the foot). Since anthropoids lack such traits too, the scientists surmise that Ida is closely connected to them. And yet, the analysis published in their paper leaves many questions unanswered. Press releases subtly claim that 95% of the evidence points out that the scientists are right. But this claim is ludicrously unscientific. The same percentage of evidence - and more – used to confirm the Ptolemaic theory that the Sun revolved around Earth; and yet the theory was completely wrong. Some critics contend that Darwinius is not an adapid at all, but a convergent subspecies of tarsier. Anyway, whatever species she may turn out to be given a more scholastic analysis, could Ida be the “missing link”?

Although the scientists who studied Darwinius deny making such statements, the promotion machine of History Channel who produced the documentary, and Brown, Little, the publisher who released the relevant book, are making the most out of this angle, calling their respective products “The Link” and the relevant website “Revealing the Link”. Which has exasperated evolutionary biologists the world over. Why? Because it chimes with the agenda of creationists who doubt the colossal corpus of evidence supporting evolution and request to see “missing fossilized links”. Because to think of evolution as an unbreakable chain made of links is woefully untrue. Species evolve from previous species following great numbers of seamless generations of gradually accumulated characteristics. There are no distinct “breaks” and therefore no “links”.

Presumably, the marketing gurus who sold the story to the media transpired that this was an excellent way to transgress the arcane scientific debates of human evolution, extract Ida from the obscurity of science journals and science meetings, and communicate her story to the public. At first glance, this may appear imaginative, commendable even. Moreover, one might argue that using a bad cliché to talk good science is sometimes de rigueur. As Jørn H. Hurum, the scientist at the University of Oslo who acquired the fossil and assembled the team of scientists who studied it, claimed: “Any pop band is doing the same thing. Any athlete is doing the same thing. We have to start thinking the same way in science.”

And yet, the sloppiness by which the scientists examined this very significant fossil if only to support their theory, their hurry to meet a publication deadline in order to coincide with History Channel’s premiering of the relevant show, as well as the ridiculous framing of Ida as the “missing link”, put all good intentions into doubt. Perhaps, cynical as it may seem, the scientists who analyzed Ida in such haste, were competing for scarce funding. Funding is undoubtedly a serious issue in today’s economic crisis. One should wonder however, if the backlash which the Ida science team currently receives will do them any good in the long run. The bad precedent of Hwang Woo-suk, the Korean geneticist “superstar” who in 2006 claimed to have cloned a human being - only to be exposed that he was lying - should have taught them a lesson. Hwang was ridiculed, discredited, and following the debacle his research got no further funding.

The only ones who are sure to gain something out of all this are the publishers and television networks who are milking the cash out of the so-called “link”. They are doing so by treating a primate fossil as a spectacle. However, what makes science different from sport, or pop music, or Paris Hilton, is that science matters much more to society in the long term. That, unlike rock stars, scientists may achieve recognition by means of truly valuable scientific discoveries and not by claiming whatever comes. The scientists who unveiled Darwinius should have known that sacrificing good science for the sake of media sensationalism does little service to science and society alike.